Vertical tube lamp



FIG. 1 is a perspective view of a vertical tube lamp showing my new design, the broken line illustration of base support is for illustrative purposes only and form no part of the claimed design;

FIG. 2 is a top plan view;

FIG. 3 is a side view wherein all side views are identical; and

FIG. 4 is a bottom plain view. 

The ornamental design for a vertical tube lamp, as shown and described. 